1. Field of Invention
This invention relates to an apparatus for ultrasonically welding the terminal end of a metal wire to a metallic wire terminal.
2. Description of the Prior Art
The end of a metal wire may be ultrasonically welded to a metal terminal by placing the wire firmly against the terminal between an anvil and an ultrasonic welding tip and applying ultrasonic energy to the wire. The energy should be applied so that the tip vibrates the pieces to be welded, to intermolecularly bond the metal workpieces one to another.
Methods of generation of ultrasonic vibration are well known in the prior art (e.g., U.S. Pat. Nos. 3,053,124; 3,328,610; 3,444,612; and 3,602,421). A typical frequency of vibration may be twenty thousand cycles per second.
However, as the wire end to be welded to the metallic wire terminal may be in a plastic state during the welding process and therefore spread or splayed, it is important that a compression chamber be formed tightly around the wire end during the welding process. This comparison chamber should be formed by elements that are preferably spring-loaded, thereby maintaining localized spot pressure of the wire end against the terminal during and throughout the welding process to prevent the wire end from splaying along the terminal even though confined within the compression chamber. The prior art is deficient in providing such a device.